hush: readability improvements.

fix some more obscure bugs.
 a new redir4.tests is known to fail.

shell/hush_test/hush-misc/redir1.tests

@@ -1,3 +1,9 @@
+rm shell_test_$$ 2>/dev/null
+var=bad
+>shell_test_$$ var=ok
+echo "Test 0:  var:$var"
+test -f shell_test_$$ && echo "File created:ok"
+
 rm shell_test_$$ 2>/dev/null
 var=bad
 var=ok >shell_test_$$